<template>
  <view
    class="previewImage"
    :style="{ 'background-color': 'rgba(0,0,0,' + opacity + ')' }"
    v-if="show"
    @click="close"
    @touchmove.stop.prevent
  >
    <swiper
      class="swiper"
      :current="index"
      @change="swiperChange"
      :disable-touch="swiper"
      :circular="circular"
    >
      <swiper-item
        v-for="(img, i) in imgs"
        :key="'swiper-item-' + i"
        :id="'swiper-item-' + i"
      >
        <movable-area class="marea" scale-area>
          <movable-view
            :id="'movable-view-' + i"
            :key="'movable-view-' + i"
            class="mview"
            direction="all"
            :out-of-bounds="false"
            :inertia="true"
            damping="90"
            friction="2"
            scale="true"
            scale-min="1"
            scale-max="4"
            :scale-value="scale"
            @scale="onScale"
            @change="movableChange"
          >
            <image
              :id="'image-' + i"
              :key="'movable-view' + i"
              class="image"
              :src="img.imgUrl"
              :style="{ transform: 'rotateZ(' + deg + 'deg)' }"
              :data-index="i"
              :data-src="img"
              mode="widthFix"
              @touchmove="handletouchmove"
              @touchstart="handletouchstart"
              @touchend="handletouchend"
            />
          </movable-view>
        </movable-area>
      </swiper-item>
    </swiper>
    <view class="page" v-if="imgs.length > 0">
      <text class="text">{{ index + 1 }} / {{ imgs.length }}</text>
    </view>
    <view class="save" v-if="saveBtn" @click.stop.prevent="save">
      <u-button
        text="下载图片(5.24MB)"
        shape="circle"
        color="#363636"
      ></u-button>
    </view>
    <view class="rotate">
      <u-icon
        name="eye"
        color="#fff"
        size="24rpx"
        label-size="24rpx"
        label-color="#fff"
        label="111"
      ></u-icon>
      <u-icon
        name="download"
        color="#fff"
        size="24rpx"
        label-size="24rpx"
        label-color="#fff"
        label="0"
      ></u-icon>
    </view>
    <view
      class="desc"
      v-if="
        descs.length > 0 &&
        descs.length == imgs.length &&
        descs[index].length > 0
      "
      >{{ descs[index] }}</view
    >
  </view>
</template>

<script>
export default {
  name: "ksj-previewImage", //插件名称
  props: {
    imgs: {
      //图片列表
      type: Array,
      required: true,
      default: () => {
        return [];
      },
    },
    descs: {
      //描述列表
      type: Array,
      required: false,
      default: () => {
        return [];
      },
    },
    //透明度,0到1之间。
    opacity: {
      type: Number,
      default: 0.8,
    },
    //保存按键
    saveBtn: {
      type: Boolean,
      default: true,
    },
    //旋转按键
    rotateBtn: {
      type: Boolean,
      default: true,
    },
    //循环预览
    circular: {
      type: Boolean,
      default: false,
    },
  },
  data() {
    return {
      swiper: false, //是否禁用
      show: false, //显示状态
      index: 0, //当前页
      deg: 0, //旋转角度
      time: 0, //定时器
      interval: 1000, //长按事件
      scale: 1, //缩放比例
    };
  },
  methods: {
    //比例变化
    onScale(e) {},

    //长按事件相关内容---------开始-------------------
    //接触开始
    handletouchstart(e) {
      var tchs = e.touches.length;
      if (tchs != 1) {
        return false;
      }
      this.time = setTimeout(() => {
        this.onLongPress(e);
      }, this.interval);
      return false;
    },
    //清除定时器
    handletouchend() {
      clearTimeout(this.time);
      if (this.time != 0) {
        //处理点击时间
      }
      return false;
    },
    //清除定时器
    handletouchmove() {
      clearTimeout(this.time);
      this.time = 0;
    },
    // 处理长按事件
    onLongPress(e) {
      var src = e.currentTarget.dataset.src;
      var index = e.currentTarget.dataset.index;
      var data = { src: src, index: index };
      this.$emit("longPress", data);
    },
    //长按事件相关内容---------结束-------------------

    //图片改变
    swiperChange(e) {
      this.index = e.target.current; //更新当前图片index

      this.$nextTick(function () {
        this.scale = 1;
      });

      //this.deg = 0; //旋转角度
      //this.swiper=true;
    },

    //移动变化
    movableChange(e) {
      //console.log(e);
      /* if(this.old.scale <= 1){
				this.swiper=false;
			}else if(e.detail.x===0){
				this.swiper=false;
			} */
    },

    //保存
    save(e) {
      var _this = this;
      var src = this.imgs[this.index];
      //#ifdef MP-WEIXIN
      //提前向用户发起授权请求
      uni.authorize({
        scope: "scope.writePhotosAlbum",
        success() {
          console.log("kxj-previewImage:允许储存");
          _this.downloadImg(src);
        },
      });
      //#endif

      //#ifdef APP-PLUS
      this.downloadImg(src);
      //#endif

      //#ifdef H5
      //非同源图片将直接打开
      var abtn = document.createElement("a");
      abtn.href = src;
      abtn.download = "";
      abtn.target = "_blank";
      abtn.click();
      //#endif
    },

    //下载并保存文件
    downloadImg(src) {
      //下载图片文件
      uni.showLoading({
        title: "大图提取中",
      });
      uni.downloadFile({
        url: src,
        success: function (res) {
          console.log("kxj-previewImage:下载成功");
          uni.hideLoading();
          uni.saveImageToPhotosAlbum({
            filePath: res.tempFilePath,
            success: () => {
              uni.showToast({
                title: "已保存至相册",
                duration: 1000,
              });
            },
          });
        },
        fail: function () {
          uni.hideLoading();
          uni.showToast({
            title: "图片下载失败",
            icon: "none",
            duration: 1000,
          });
        },
      });
    },

    //旋转
    rotate(e) {
      this.deg = this.deg == 270 ? 0 : this.deg + 90;
    },
    //打开
    open(e) {
      if (e === null || e === "") {
        console.log("kxj-previewImage:打开参数无效");
        return;
      }

      if (!isNaN(e)) {
        if (e >= this.imgs.length) {
          console.log("kxj-previewImage:打开参数无效");
        } else {
          this.index = e;
        }
      } else {
        var index = this.imgs.indexOf(e);
        if (index === -1) {
          this.imgs = [e];
          this.index = 0;
          console.log(
            "kxj-previewImage:未在图片地址数组中找到传入的图片，已为你自动打开单张预览模式",
          );
        } else {
          this.index = this.imgs.indexOf(e);
        }
      }
      console.log("kxj-previewImage:当前预览图片序号" + this.index);
      this.show = true;
    },
    //关闭
    close(e) {
      this.show = false;
      this.index = 0; //当前页
      this.deg = 0; //旋转角度
      this.time = 0; //定时器
      this.interval = 1000; //长按事件
      this.scale = 1; //缩放比例
    },
  },
};
</script>

<!--使用scss,只在本组件生效-->
<style lang="scss" scoped>
.previewImage {
  z-index: 999;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #000000;
  user-select: none;
  .swiper {
    width: 100%;
    height: 100%;
    .marea {
      height: 100%;
      width: 100%;
      position: fixed;
      overflow: hidden;
      .mview {
        display: flex;
        align-items: center;
        justify-content: center;
        width: 100%;
        height: auto;
        min-height: 100%;
        .image {
          width: 100%;
        }
      }
    }
  }

  .page {
    position: absolute;
    width: 100%;
    top: 44px;
    text-align: center;
    .text {
      color: #fff;
      font-size: 26rpx;
      background-color: rgba(0, 0, 0, 0.5);
      padding: 3rpx 16rpx;
      border-radius: 20rpx;
      user-select: none;
    }
  }
  .save {
    position: absolute;
    left: 24rpx;
    width: fit-content;
    height: 56rpx;
    bottom: 50rpx;
    text-align: center;
    padding: 10rpx;
    .text {
      background-color: rgba(0, 0, 0, 0.5);
      color: #fff;
      font-size: 30rpx;
      border-radius: 20rpx;
      border: 1rpx solid #f1f1f1;
      padding: 6rpx 22rpx;
      user-select: none;
    }
    .text:active {
      background-color: rgba(100, 100, 100, 0.5);
    }
  }
  .rotate {
    position: absolute;
    right: 24rpx;
    width: fit-content;
    display: flex;
    gap: 16rpx;
    height: 56rpx;
    bottom: 36rpx;
    text-align: center;
    padding: 10rpx;
    .text {
      background-color: rgba(0, 0, 0, 0.5);
      color: #fff;
      font-size: 30rpx;
      border-radius: 20rpx;
      border: 1rpx solid #f1f1f1;
      padding: 6rpx 22rpx;
      user-select: none;
    }
    .text:active {
      background-color: rgba(100, 100, 100, 0.5);
    }
  }
  .desc {
    position: absolute;
    top: 0;
    width: 100%;
    padding: 5rpx 10rpx;
    text-align: center;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    background-color: rgba(0, 0, 0, 0.5);
    color: #fff;
    font-size: 28rpx;
    letter-spacing: 3rpx;
    user-select: none;
  }
}
</style>
